I am not a zoologist or a veterinarian so when I saw an article on non-invasive wildlife monitoring of cheetahs, I was intrigued.  You can read the article here.

Having never heard of WildTrack before, I checked out their website http://www.wildtrack.org/ and found it very interesting.  Apparently they have developed a non-invasive technique to monitor endangered species and therefore provide wildlife conservation with a great new resource for the future.  It works in a similar way to that which allows humans to be identified by fingerprints.  And, by photographing paw prints in the wild, researchers can monitor cheetahs without ever seeing them.  This footprint identification technique or FIT, along with other techniques based on biometrics, has been used in the past for tracking polar bears and bengal tigers.  I think there needs to be more verification that each animal in a particular species has a unique "footprint" but it seems reasonable and should be a definite plus for both the animals and those that work so hard to preserve endangered species for future generations.